L-Carnosine, a dipeptide, can enhance frontal lobe function or be
neuroprotective. It can also correlate with gamma-aminobutyric acid
(GABA)-homocarnosine interaction, with possible anticonvulsive effects. We
investigated 31 children with autistic spectrum disorders in an 8-week,
double-blinded study to determine if 800 mg L-carnosine daily would result in
observable changes versus placebo. Outcome measures were the Childhood Autism Rating Scale, the Gilliam Autism Rating Scale, the Expressive and ReceptiveOne-Word Picture Vocabulary tests, and Clinical Global Impressions of Change.
Children on placebo did not show statistically significant changes. After 8
weeks on L-carnosine, children showed statistically significant improvements on the Gilliam Autism Rating Scale (total score and the Behavior, Socialization,
and Communication subscales) and the Receptive One-Word Picture Vocabulary test (all P < .05). Improved trends were noted on other outcome measures. Although the mechanism of action of L-carnosine is not well understood, it may enhance neurologic function, perhaps in the enterorhinal or temporal cortex.